The low force level detection system and method relates to systems and methods for detecting force and, more particularly, systems and methods for detecting low force levels in electromechanical brake systems.
Electromechanical brake systems typically include a housing, a rotor, brake pads, an actuator/caliper and a motor. The actuator is adapted to drive the brake pads into engagement with the rotor, thereby clamping the rotor between the pads. The motor drives the actuator into engagement with the brake pads and the rotor. Therefore, the amount of force applied to the rotor by the brake pads is a function of the distance that the actuator is advanced by the motor.
Prior art systems attempt to detect the position of the actuator at the onset of force (i.e., the point of initial contact). Then, assuming that the brake system can be modeled as a spring, the braking force may be calculated using Hooke's law:F0=k(x0−xi)  (Eq. 1)wherein F0 is the braking force, k is the spring function of the system, xi is the position of the actuator at the onset of force and x0 is the position of the actuator at a subsequent time.
Such prior art systems attempt to detect the actual contact point. However, at the onset of force, the signal to noise level of the distinguishable signals is small and difficult to use. Therefore, such systems often encounter difficulty identifying the point at which contact is made and/or force is applied, thereby giving rise to inaccurate measurements of braking force.
Accordingly, there is a need for an improved system and method for estimating the contact force between two bodies.